While performing periodical refraction examination, under which circumstances there should be a need to re-frame a new pair of glasses ?
In the previous article, we have introduced the importance of periodical refraction examination for your eyes. However what are the details that we need to focus as a criterion in re-framing a new pair of glasses based on the examination results? In regards to this matter, we ought to analyze and make judgments based on scientific manner.
Due to the fact that changes in the refractive state of human’s eye is gradual and continuous, though in a short time changes may seem negligible however we are unable to jump into the same simple conclusion for changes that may happen between the period of 6 months to 1 year. As the changes on the refractive state of a prescription glasses is a result of accumulative process, it is imperative that much importance has to be placed on past historical accumulative refractive changes.
Is it often that we hear people around us commenting that “I have been using my existing prescription glasses for the past decade with no issues.” This only shows that the individual may not realize the corrective relationship between the eyes and prescription glasses. It is necessary to note that it is rather unreasonable to utilize the same pair of prescription lenses for a decade.
So, how long is the lenses replacement interval can be considered as reasonable then? In fact, there is no rule of thumb for such replacements, as long as replacement is done when the need arises. Once again we will find that regular refraction examinations are very necessary.
Taking into account the dynamics of refractive changes and necessary corrective measures needed, it is concluded that any of the following conditions should require prescription lens replacement:
- Change of diopter > 0.75D;
- Astigmatic axis deflection angle> 15 ° (high astigmatism> 10 °), (for deflection levels around 5–10 °, it is dependent on wearer’s corrective requirements, as 5–10 ° deflection situations may not require prescription glasses);
- Obvious inconsistencies between the optical center and interpupillary distance (IPD);
- Wearers who are comfortable of using corrective lenses with excessively high diopter values for daily usage
- Wearers who are not comfortable with unspecified corrective lenses
Therefore importance must be given if the latest overall result has changes (as compared to previous results) during the latest regular refraction examination, especially if the changes are similar to what is mentioned above. It is highly suggested that to proceed with re-framing a new pair of prescription glasses or to have further examinations performed under the guidance of a optometrist.